(i) Technical Field
The present invention relates to a printing system and a printing method.
(ii) Related Art
In a production printing system, the processing speed in a marking technology such as inkjet has been increasing. In particular, high speed printing faster than 2500 ppm (pages per minute) is put to practical use in a printing system for continuous paper. As a marking technology has been improving, it is desired that the speed of processing for generating a raster image of print job data be increased, the processing being performed by a raster image processor (RIP). The performance of an RIP greatly depends on the performance of the central processing unit (CPU) of hardware.
Recently, print data has been expressed in full colors and has been realizing higher resolution. The required throughput for full-color (CMYK) data is four times faster than that for black and white gray-scale data as a result of simple calculation. In addition, when a resolution is doubled, the size of image data is quadrupled. From this time forward, the required RIP throughput necessary for a system controller tends to be higher.
When RIP processing takes a longer time than expected, generation of an image does not keep up with the output speed of a printer. In particular, in the case where a printing system for continuous paper once starts running, the printing system is incapable of stopping operation immediately. Thus, if generation of an image to be printed is not completed in time, a piece of blank paper is output. This is not only a waste of paper but also is troublesome because unnecessary pieces of blank paper need to be removed in a postprocessing process. Thus, blank paper is preferably prevented from being output.
In the case where the CPU of a system controller is changed to a faster one, although the RIP processing speed increases, the manufacturing cost also increases. On the other hand, there is a method (in-advance raster image processing (RIP)) for performing RIP on all job data in advance before printing is started. According to this method, an issue in that RIP processing is not completed in time does not occur.
In a print place where a large number of bills and the like are output consecutively, first, part of the job is extracted and test printing is performed on the extracted part before performing actual printing on a certain job. Here, it is checked whether or not no errors occur due to a page description language (PDL) of the job and it is also checked whether or not processing will be completed in time without performing in-advance RIP. In accordance with this result, whether or not to perform in-advance RIP may be determined and, thereafter, a task process of actual printing of the entire job may be performed.
However, in the case where in-advance RIP is performed, there is an issue in that an additional time is necessary to perform RIP processing on all job data in advance. In addition, a storage device such as a hard disk drive (HDD) is necessary to temporarily store generated image data. In a production printing system, there may be many cases where several tens of thousands to several hundreds of thousands of pages are consecutively printed. The necessary storage capacity may exceed several tens of gigabytes (GB). Thus, direct printing is preferably performed without performing in-advance RIP, if possible, in terms of work time and cost.